MSE 201 LAB II: Part b

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MSE 201 LAB II Part b

• Annealing Copper Alloys

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Lab Overview

• Each alloy (Pure, 5 Zn, 10 Zn, 20 Zn) will be
  annealed for 45 minutes at 8 temperatures
• 200C, 250C, 300C, 350C, 400C, 500C, 600C,
  and 800C
• Hardness after each anneal will show amount of
  recrystallization or grain growth
• PROCEED TO FURNACE ROOM TO CONDUCT ANNEALING

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What is Recrystallization?

• Recovering damage and forming new grains by
  addition of heat

(click to play)
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Stages During Annealing

• I Recovery
• II Recrystallization
• III Grain Growth

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Goal Plot of Hardness vs. Annealing Temp
I Recovery
II Recrystallization
III Grain Growth
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Joined Plots
Hardness vs. CW and Annealing Temperature
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Stress Free Grain
http//www.copper.org/resources/properties/microst
ructure/brasses.html
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http//www.copper.org/resources/properties/microst
ructure/brasses.html
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Slip Lines
Deformation Bands
Distorted Grains
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New Crystal Formation
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Microstructure Examination

• 5 Zinc samples will be examined
• Sample 242 Shows effects of cold working
• Sample 243 Shows effects of annealing
  temperature.

• Look for
• Grain Boundaries
• Stress Free Grains
• Distorted Grains
• New Crystals
• Deformation Bands
• Slip Lines
• Annealing Twins
• Etch Pits
• Scratches

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After Removing Samples

• Remove oxide scale with sand paper
• Average hardness results for each sample
  (HRF/HRB) and convert to DPH
• Make sure data sheet is completely filled out
• Place samples in recycle box.
• Turn Data Sheet in to TA

Remember There is a report DUE NEXT WEEK!